The Fort Peck Sexual Health Project will identify the individual, family, community, and environmental factors influencing the sexual and reproductive health among young male and female Native Americans ages 15 to 18 years old in a rural, frontier setting. The study focuses specifically on the Fort Peck Reservation in northeastern Montana, home to the Assiniboine and Sioux tribes. We hypothesize that high STI rates and unplanned pregnancies are a marker for deeper underiying health issues operating and interacting at the individual, family, community, and environmental levels. The study will examine several interrelated ecological factors that are likely to be influencing the sexual risk taking behaviors of 15 to 18 year old Native American males and females. The aims of this study are 1) to identify the cognitive behavioral factors contributing to sexual risk taking behaviors among male and female Native American adolescents, 2) to examine which social and cultural norms contribute to sexual risk taking behaviors among male and female Native adolescents, including parenting and transmission of parental values, cultural beliefs about the value of children, atfitudes and beliefs about sex, and the traditional and contemporary religious belief systems with regard to sex, 3) to identify the environmental and contextual factors that might contribute to sexual risk taking behaviors among male and female Native American adolescents, and 4) to develop and pilot an intervention. The Fort Peck Sexual Health Project is a community based participatory research (CBPR) project and uses a concurrent qualitative and quantitative research design. The results ofthe Fort Peck Sexual Health Project will be used to construct an innovative, community designed and implemented, intervention to reduce STI rates and prevent unplanned pregnancies among Native Americans living in Montana as a model for other tribal communities in rural, fronfier environments.